Question
Wed March 26, 2014 By: Sanskrati Gawande

how so2 cause pollution ? give steps to control it?

Expert Reply
Thu March 27, 2014

Sulphur dioxide (SO2) causes pollution as follows:

It combines with water vapour present in the atmosphere to form sulphuric acid. This causes acid rain.

It is harmful as follows:

a)      Acid rain damages soil, plants, and buildings, especially those made of marble.

b)      Even in very low concentrations, SO 2 causes irritation in the respiratory tract. It causes throat and eye irritation and can also affect the larynx to cause breathlessness.

c)      It is extremely harmful to plants. Plants exposed to sulphur dioxide for a long time lose colour from their leaves. This condition is known as chlorosis. This happens because the formation of chlorophyll is affected by the presence of sulphur dioxide.

Steps to control the pollution by SO2 as follows:

 SO2 emitted into the atmosphere from industries. It is the main contributors to acid deposition Additionally, individuals and society as a whole can participate in various efforts to help reduce acid deposition:

  • Understand acid deposition’s causes and effects
  • Clean up smokestacks and exhaust pipes
  • Use alternative energy sources
  • Restore a damaged environment
  • Look to the future
  • Take action as individuals
  • Reduce industrial SO2 emission
  • A reduction in the atmospheric emissions of SO2 produced by fossil fuel combustion processes can be achieved at one of three stages, as follows.
  • 1. Reducing the sulphur content of the fuel before combustion: Emissions of SO2 are proportional to the sulphur content of the fuel, although with regard to coal a proportion, usually less than 10%, is retained in the ash. Therefore, one of the simplest ways to reduce the amount of SO2 released from the combustion process can be achieved by switching to a fuel that has a lower sulphur content, i.e. burning low sulphur coal or gas instead of high sulphur coal.
  • 2. Sulphur Removal During CombustionA number of technologies to prevent the production and release of SO2 during combustion have been developed over the past decade, but very few have achieved wide commercial application to date. The most developed are the Fluidised Bed Combustion (FBC) process and the integrated Gasification Combined Cycle (IGCC) system.
  • 3. Removal of Sulphur after Combustion: Emissions of SO2 generated during the combustion of fossil fuels can be reduced by treating the flue gases before they are emitted into the atmosphere via the stack; this is termed Flue Gas Desulphurisation (FGD). Flue gas desulphurisation systems can be classified as either Regenerable or Non-regenerable.
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